The present invention relates to a display device such as a television or monitor and more particularly to an illuminating device for irradiating rays of light uniformly on a liquid crystal panel and a liquid crystal display device using the same.
A light emitting diode (hereinafter referred to as LED) package comprised of LED's and a lens is disclosed in JP-A-2003-8068 (Document 1) or JP-A-2003-8081 (Document 2).
The contents of Patent Document 1 reads “A lens has a lens proper which comprises a center axis extending along a longitudinal direction of the lens proper, a first surface for coupling to a light source, a saw-toothed lens portion for refracting light emitted from the light source in such a manner that most of the light going out of the saw-toothed lens portion is made to be substantially vertical to the center axis of the lens proper and a funnel-shaped lens portion connected to the saw-toothed lens portion to reflect the light emitted from the light source in such a manner that most of the light going out of the funnel-shaped lens portion is made to be substantially vertical to the center axis of the lens proper.”
“High Brightness Direct LED Backlight for LCD-TV” by R. West, SID03 DIGEST, pp. 1262-1265 (Document 3) is concerned with a liquid crystal display device using, as a backlight, an illuminating device employing an LED package comprised of LED's and a lens.
“Adaptive Dimming Technique with Optically Isolated Lamp Groups” by T. Shiga, SID05 DIGEST, pp 992-995 (Document 4) discloses a technique for improving quality of motion pictures by interposing a reflector between lamps in a cold cathode fluorescent lamp (CCFL) backlight but it does not refer to a light emitting diode (LED) representing a point light source.